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-rw-r--r--butl/utility53
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+// file : butl/utility -*- C++ -*-
+// copyright : Copyright (c) 2014-2015 Code Synthesis Ltd
+// license : MIT; see accompanying LICENSE file
+
+#ifndef BUTL_UTILITY
+#define BUTL_UTILITY
+
+#include <cstring> // strcmp
+
+namespace butl
+{
+ // Key comparators (i.e., to be used in sets, maps, etc).
+ //
+ struct compare_c_string
+ {
+ bool operator() (const char* x, const char* y) const
+ {
+ return std::strcmp (x, y) < 0;
+ }
+ };
+
+ struct compare_pointer_target
+ {
+ template <typename P>
+ bool operator() (const P& x, const P& y) const {return *x < *y;}
+ };
+
+ // Support for reverse iteration using range-based for-loop:
+ //
+ // for (... : reverse_iterate (x)) ...
+ //
+ template <typename T>
+ class reverse_range
+ {
+ T& x_;
+
+ public:
+ reverse_range (T& x): x_ (x) {}
+
+ auto begin () -> decltype (this->x_.rbegin ()) {return x_.rbegin ();}
+ auto end () -> decltype (this->x_.rend ()) {return x_.rend ();}
+ };
+
+ template <typename T>
+ inline reverse_range<T>
+ reverse_iterate (T& x) {return reverse_range<T> (x);}
+
+ template <typename T>
+ inline reverse_range<const T>
+ reverse_iterate (const T& x) {return reverse_range<const T> (x);}
+}
+
+#endif // BUTL_UTILITY